title: Immunohistochemistry and pathology of multiple Great Lakes fish from mortality events associated with viral hemorrhagic septicemia virus type IVb.
abstract: A novel viral hemorrhagic septicemia virus (VHSV) (genotype IVb) has been isolated from mortality events in a range of wild freshwater fish from the Great Lakes since 2005. In 2005 and 2006, numerous new freshwater host species (approximately 90 fish from 12 different species) were confirmed to have VHSV by cell culture and reverse transcriptase polymerase chain reaction. A prominent feature observed in infected fish were the petechial and ecchymotic haemorrhages on the body surface and in visceral organs, as well as serosanguinous ascites; however, many fish had few and subtle, gross lesions. Histologically, virtually all fish had a vasculitis and multifocal necrosis of numerous tissues. Excellent correlation was found between the presence of VHSV IVb antigen detected by immunohistochemistry and the pathological changes noted by light microscopy. Intact and degenerate leukocytes, including cells resembling lymphocytes and macrophages, also had cytoplasmic viral antigen. By contrast, renal tubules and gonadal tissues (ovary and testis), were strongly immunopositive for VHSV IVb, but no lesions were noted.
authors.affiliation: Fish Pathology Laboratory, Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Al-Hussinee
authors.forename: S
authors.initials: S
authors.lastname: Lord
authors.forename: R M W
authors.initials: RM
authors.lastname: Stevenson
authors.forename: R N
authors.initials: RN
authors.lastname: Casey
authors.forename: G H
authors.initials: GH
authors.lastname: Groocock
authors.forename: K L
authors.initials: KL
authors.lastname: Britt
authors.forename: K H
authors.initials: KH
authors.lastname: Kohler
authors.forename: G A
authors.initials: GA
authors.lastname: Wooster
authors.forename: R G
authors.initials: RG
authors.lastname: Getchell
authors.forename: P R
authors.initials: PR
authors.lastname: Bowser
authors.forename: J S
authors.initials: JS
authors.lastname: Lumsden
mesh_terms: D000818:Animals; D005260:Female; D005393:Fish Diseases / Q000453:epidemiology / Q000473:pathology / Q000821:virology*; D005399:Fishes / Q000145:classification; D006114:Great Lakes Region; D007150:Immunohistochemistry; D051379:Mice; D029141:Novirhabdovirus / Q000145:classification*; D010053:Ovary / Q000821:virology; D018353:Rhabdoviridae Infections / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary* / Q000821:virology